Problem while tryng to connect fleshdesk to my idp

I’m trying to connect fleshdesk to external idp using openId. The connection works fine, but I would like to customize it. I would like that fleshdesk add more parameters for the connection to my idp in addition to those present in the configuration phase. I tried to insert them directly into the URL of the button that is generated to make the SSO connection, but they are overwritten by the following calls that are made by fleshdesk. What should I do?